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Journal of Materials Science & Technology 2012年第12期28卷 1123-1129页

作者： Zhaorui Li Jianbin Wang Yuanjian Tong lianghua xu National Carbon Fiber Engineering Research Center Beijing University of Chemical Technology Beijing 100029 China

Polyacrylonitrile （PAN） based carbon fibers with different surface morphology were electrochemically treated in 3 wt% NH4HCO3 aqueous solution with current density up to 3.47 A/m 2 at room temperature, and surface structures, surface morphology and residual mechanical properties were characterized. The crystallite size （La） of carbon fibers would be interrupted due to excessive electrochemical etching, while the crystallite spacing （d（002）） increased as increasing current density. The disordered structures on the surface of carbon fiber with rough surface increased at the initial oxidation stage and then removed by further electrochemical etching, which resulting in continuous increase of the extent of graphitization on the fiber surface. However, the electrochemical etching was beneficial to getting ordered morphology on the surface for carbon fiber with smooth surface, especially when the current density was lower than 1.77 A/m 2 . The tensile strength and tensile modulus could be improved by 17.27% and 5.75%, respectively, and was dependent of surface morphology. The decreasing density of carbon fibers probably resulted from the volume expansion of carbon fibers caused by the abundant oxygen functional groups intercalated between the adjacent graphite layers.

关键词： Carbon fibers Anodic oxidation Structural evolution Tensile property Surface morphology

Energy-saving design and optimization of pressure-swing-assisted ternary heterogenous azeotropic distillations

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Chinese Journal of Chemical Engineering 2024年第4期68卷 1-7页

作者： Lianjie Wu Kun Lu Qirui Li lianghua xu Yiqing Luo Xigang Yuan Tianjin Key Laboratory of Organic Solar Cells and Photochemical Conversion College of Chemical and Chemical EngineeringTianjin University of TechnologyTianjin 300384China State Key Laboratory of Chemical Engineering Tianjin UniversityTianjin 300072China

A huge amount of energy is always consumed to separate the ternary azeotropic mixtures by *** heterogeneous azeotropic distillation and the pressure-swing distillation are two kinds of effective technologies to separate heterogeneous azeotropes without entrainer *** give better play to the synergistic energy-saving effect of these two processes,a novel pressure-swing-assisted ternary heterogeneous azeotropic distillation(THAD)process is proposed *** this process,the ternary heterogeneous azeotrope is decanted into two liquid phases before being refluxed into the azeotropic distillation column to avoid the aqueous phase remixing,and three columns'pressures are modified to decrease the flowrates of the recycle *** the dividing wall column and heat integration technologies are introduced to further reduce its energy consumption,and the pressureswing-assisted ternary heterogeneous azeotropic dividing-wall column and its heat integration structure are achieved.A genetic algorithm procedure is used to optimize the proposed *** design results show that the proposed processes have higher energy efficiencies and lower CO_(2)emissions than the published THAD process.

关键词： Distillation Separation Process control Process systems

Copolymerization of Acrylonitrile/1-Vinyl-3-Ethylimidazolium Bromide and Rheological, Thermal Properties of the Copolymer

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Transactions of Tianjin University 2019年第1期25卷 85-90页

作者： Yuanjian Tong Bowen Zhang Changqing Li lianghua xu State Key Laboratory of Organic–Inorganic Composites Beijing University of Chemical Technology Key Laboratory of Carbon Fiber and Functional Polymer Ministry of Education Beijing University of Chemical Technology

Acrylonitrile(AN)/1-vinyl-3-ethylimidazolium bromide(VIMB) copolymer was prepared via solution polymerization using dimethyl sulfoxide(DMSO) as a solvent and azodiisobutyronitrile as an initiator. The effects of comonomer VIMB on the polymerization, rheological properties of the polymer solution and thermal properties of the copolymer were investigated. The ionic liquid VIMB resulted in higher polymerization conversion ratio and higher average molecular weight when copolymerized with AN than itaconic acid(ITA). Rheological measurements indicated that the transition shear rate increased linearly with increasing temperature for P(AN/ITA)/DMSO solution, while an exponential growth with temperature was observed for P(AN/VIMB)/DMSO solution. The exothermic peaks of DSC curves in N_2 appeared at 276.67 and 257.34 °C for P(AN/VIMB) and P(AN/ITA), respectively. As a potential comonomer of AN for PAN carbon fibers, the VIMB resulted in about 7% higher char yield in N_2, and 23.7% less weight loss at 600 °C in air than ITA copolymer.

关键词： Carbon fiber Copolymer Polyacrylonitrile Ionic liquid Thermal properties

Spectroscopic studies of the interaction between methyleneblue and G-quadruplex

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Chinese Science Bulletin 2006年第14期51卷 1687-1692页

作者： SUN Hongxia XIANG Junfeng ZHANG Yazhou xu Guangzhi xu lianghua TANG Yalin College of Material Science and Engineering Beijing University ofChemical Technology Beijing 100029 China Institute of Chemistry Chinese Academy of Sciences Beijing 100080China

G-rich single-stranded DNA (5′-TTAG-GG-3′) adopted a G-quadruplex structure in buffercontaining potassium ions. The spectroscopic featureand the interaction between methylene blue andG-quadruplex have been investigated by circular di-chroism, and nuclear magnetic resonance spectros-copy. The UV-Vis absorption and fluorescence spec-tral results show that the fluorescence behavior ofMB by single-stranded DNA fits Stern-Volmer staticquenching equation very well and they formed 1︰1complexes; dimeric G-quadruplexes were bound toMB with 1︰1 or 2︰1, and their equilibrium constantswere 1.047×105 and 8.79×104 L/mol, *** on the above results and 1H-NMR spectraldata, one may conclude that MB stacked either theterminal tetrads to form 1︰1 complexes or betweentwo terminal tetrads of G-quadruplexes to form 1︰2sandwich complexes with G-qudruplexes.

关键词：甲基蓝吸收荧光分光检查钾离子

Gradient distribution of radial structure of PAN-based carbon fiber treated by high temperature

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Progress in Natural Science:Materials International 2014年第1期24卷 31-34页

作者： Haitao Wang Yu Wang Ting Li Shuai Wu lianghua xu National Carbon Fiber Engineering Research Center Beijing University of Chemical Technology

High-performance graphite fibers were prepared and analyzed. The gradient distribution of radial structure of PAN-based carbon fibers was characterized by two different Raman test methods(incident laser beam perpendicular to and parallel to the fiber axis) and studied by the distribution of graphitization degree. Meanwhile difference between the two Raman test methods was used to describe the orientation of the graphite crystallite along the fiber axis. The results showed that the radial structure of PAN-based carbon fiber presented different gradient distribution states at different heat treatment temperatures,and the graphitization degree in the skin region changed more rapidly compared with the core region since the skin region was more affected by temperature which resulted in the obvious difference between skin and core *** difference of graphitization degree(Δg) characterized by two different Raman test methods increased with heat treatment temperature,indicating that the high temperature treatment(HTT) promoted further stacking of graphite crystallite,and the orientation degree of the graphite crystallite along the fiber axis was continuously increased.

关键词： HTT Radial structure Gradient distribution Graphite crystallite

突破原丝瓶颈效应加速我国PAN炭纤维技术的发展

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材料导报 2000年第11期14卷 14-15页

作者：徐梁华北京化工大学北京100029

聚丙烯腈基炭纤维是高新技术领域中的重要原材料,制约其技术发展的瓶颈是原丝的研究。分析了长期以来国内原丝研究存在的综合基础弱,力量薄,研究单一,缺乏创新等问题,结合北京化工大学开展的T300及更高性能炭纤维原丝技术研究工作,探讨... 详细信息

聚丙烯腈基炭纤维是高新技术领域中的重要原材料,制约其技术发展的瓶颈是原丝的研究。分析了长期以来国内原丝研究存在的综合基础弱,力量薄,研究单一,缺乏创新等问题,结合北京化工大学开展的T300及更高性能炭纤维原丝技术研究工作,探讨并提出了提高原丝基础和工艺研究的建议,认为点面结合、创新思维和不懈努力、集中攻关与广泛协作等是提高原丝研究水平的基础与保证,同时强调要高度重视工艺与装备研究、开发具有自主知识产权技术的重要性。

关键词：聚丙烯腈原丝碳纤维中国炭纤维工业技术发展

湿法纺丝Amid-CNT/PAN复合纤维的结构与性能

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复合材料学报 2010年第6期27卷 9-15页

作者：张海龙靳玉伟徐樑华北京化工大学碳纤维及功能高分子教育部重点实验室北京100029

通过溶液聚合得到胺化碳纳米管(Amid-CNT)/聚丙烯腈(PAN)复合溶液,采用湿法纺丝技术制备了Amid-CNT/PAN复合纤维。利用红外光谱、拉曼光谱、差示扫描量热仪、热失重仪和扫描电镜等方法分析Amid-CNT对PAN纤维结构的影响。结果表明:Amid-... 详细信息

通过溶液聚合得到胺化碳纳米管(Amid-CNT)/聚丙烯腈(PAN)复合溶液,采用湿法纺丝技术制备了Amid-CNT/PAN复合纤维。利用红外光谱、拉曼光谱、差示扫描量热仪、热失重仪和扫描电镜等方法分析Amid-CNT对PAN纤维结构的影响。结果表明:Amid-CNT与PAN大分子之间有很强的化学作用力;Amid-CNT在复合纤维中具有很高程度的取向,使PAN纤维中氰基的取向从1.61提高到了2.30;复合纤维在空气中的起始放热温度相对PAN纤维从212.30℃提前到206.01℃,反应放热量从3054 J/g降低到2346 J/g;复合纤维比PAN纤维的起始失重温度提前了3.7℃,在700℃时的剩余质量提高了13.5%;复合纤维的断面比PAN纤维具有更多的絮状结构。

关键词：碳纳米管聚丙烯腈取向湿法纺丝复合纤维

国产高性能聚丙烯腈基碳纤维技术特点及发展趋势

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科技导报 2018年第19期36卷 43-51页

作者：徐樑华王宇北京化工大学国家碳纤维工程技术研究中心

聚丙烯腈基碳纤维兼具高性能和低比重,是轻质高强、轻质高模等高端装备轻量化的首选材料,是高性能纤维的典型代表,受到世界各国政府、国防与工业领域、科技与产业界的高度关注。从聚丙烯腈碳纤维材料的结构性能特征出发,介绍了聚丙烯腈... 详细信息

聚丙烯腈基碳纤维兼具高性能和低比重,是轻质高强、轻质高模等高端装备轻量化的首选材料,是高性能纤维的典型代表,受到世界各国政府、国防与工业领域、科技与产业界的高度关注。从聚丙烯腈碳纤维材料的结构性能特征出发,介绍了聚丙烯腈基碳纤维制备的工艺流程、结构与性能的相关性;从高强碳纤维被发明、高强中模碳纤维因需求牵引而研发成功、更高性能碳纤维的不断创新发明,直至进入新世纪后对高性能低成本化的重视,阐述了国际聚丙烯腈基碳纤维技术发展的4个关键阶段;分析了国产碳纤维通过自主创新,建立以二甲基亚砜为主、包含其他工艺技术的发展历程。从高强和高强中模碳纤维、高模和高模高强碳纤维、低成本大丝束碳纤维的国产化有序发展,展示了碳纤维国产化技术水平不断提高、碳纤维制备与应用不断融合的现状。最后结合国际技术发展动态和中国碳纤维技术积累基础,提出了开展颠覆性技术研究的建议,认为新型聚丙烯腈成纤技术、原材料创新和碳纤维制备过程新型热源技术等值得高度关注。

关键词：聚丙烯腈基碳纤维高性能碳纤维制备技术国产碳纤维发展历程

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水工建筑物强震动加速度记录的分析处理

地震工程与工程振动 2012年第5期32卷 26-32页

作者：许亮华郭永刚杜修力中国水利水电科学研究院北京100048 北京工业大学建筑工程学院北京100124

从工程应用角度详细介绍水工强震动加速度记录正确处理分析的方法与原理。主要介绍了震源的评估原理,强震动加速度记录预处理过程中单位换算、奇异点剔除、基线校正、滤波除噪等步骤的方法原理,后处理分析中一次、二次积分、谱分析原理... 详细信息

从工程应用角度详细介绍水工强震动加速度记录正确处理分析的方法与原理。主要介绍了震源的评估原理,强震动加速度记录预处理过程中单位换算、奇异点剔除、基线校正、滤波除噪等步骤的方法原理,后处理分析中一次、二次积分、谱分析原理。阐述了利用强震动加速度记录进行震害快速评估原理。文中以二滩拱坝强震监测台阵监测到的一次强震加速度记录的处理过程为例,以图表形式直接明了地强调指出了强震动加速度记录处理中容易发生错误的过程,并提出相应的处理方法。

关键词：水工建筑物数据处理强震监测震害评估

碳纤维形貌结构对其电化学氧化行为及其复合材料界面性能的影响

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复合材料学报 2015年第4期32卷 1218-1224页

作者：李昭锐张东徐樑华孙玉山徐鸣风中国纺织科学研究院生物源纤维制造技术国家重点实验室北京100025 北京化工大学国家碳纤维工程技术研究中心北京100029

通过调控原丝工艺,制备得到形貌结构不同、力学性能相近的PAN基碳纤维(CF),用以模拟碳纤维表面光滑与沟槽结构对其电化学氧化行为的影响。研究表明:原始形貌光滑碳纤维在电化学过程中保持形貌能力较强,相同的电化学氧化强度下,其表面氧... 详细信息

通过调控原丝工艺,制备得到形貌结构不同、力学性能相近的PAN基碳纤维(CF),用以模拟碳纤维表面光滑与沟槽结构对其电化学氧化行为的影响。研究表明:原始形貌光滑碳纤维在电化学过程中保持形貌能力较强,相同的电化学氧化强度下,其表面氧碳比高于原始表面粗糙的碳纤维,表明其氧化程度高。X射线光电子能谱(XPS)分峰结果表明,二者表面氧含量差别来自于表面羰基含量的差异。力学性能测试结果表明具有沟槽形貌的碳纤维拉伸强度及拉伸模量提高的幅度较大,其中拉伸强度提高最大值为17.3%。将氧化前后的碳纤维制备成碳纤维增强树脂基复合材料,探讨碳纤维形貌结构对其复合材料界面性能的影响。结果表明:由具有沟槽形貌的碳纤维制备得到的复合材料层间剪切强度(ILSS)较高,表明碳纤维表面物理形貌也是影响复合材料界面的重要因素。

关键词：碳纤维形貌结构电化学氧化复合材料界面